1. Field of the Invention
The present invention relates generally to an Ultra-Wide Band (UWB) wireless system, and more particularly to one which can produce high-quality Gaussian monocycle pulse trains to be used for high speed wireless transfer system in the future.
2. Description of Related Art
Ultra-Wide Band (UWB) wireless telecommunication system has been one of the focuses of attention-in the field of the latest wireless telecommunication. It is capable of high-bit-rate data transfer, and can be applied to household appliances such as audio-video equipments, digital TV, PC, or PDA. It can be used to link up the different devices and transmit the information among them. What's more, it can coexist with other existing communication systems. As a result, it has been favored in the wireless telecommunications. However, to generate pulses to be transmitted, Ultra-Wide Band (UWB) wireless telecommunication often relies on electronic devices, which have difficulty in generating such Ultra-Wide Band (UWB) pulses. On the contrary, optical signal is high-frequency signal, and has wide bandwidth, so it is easier for optical devices to generate Ultra-Wide Band (UWB) pulses than for electronic devices.
Of the available literatures concerning Ultra-Wide Band (UWB) system, McCorkle, John W.; Huynh, Phuong T.; Ochoa, Agustin demonstrate in MONOCYCLE GENERATOR (patented and published in April 2003, and numbered US 20030076136) that an Ultra-Wide Band (UWB) wireless system of Gaussian monocycle pulse as realized by way of electronic devices is of considerable commercial value.
And Carbonari, David certified in ULTRA WIDEBAND TRANSMITTER (patented and published in March 2005, and numbered US 20050047480) that a simple Ultra-Wide Band (UWB) wireless transmitter of Gaussian monocycle pulse can be of very great potential.
In addition, Kennedy, Philip T.; Melick, Bruce D.; Snyder, David M.; Baych, Leslie D. presented in HIGH BANDWIDTH DATA TRANSPORT SYSTEM (patented and published in June 2005, and numbered US20050131922) their discovery that Ultra-Wide Band pulse can be employed to transport data via different media, that it can be applied to optical fiber transport, cable TV line transport and so on, and that Ultra-Wide Band signal is highly commercial for its wider applicability in transporting data.
In future digitalized household, electronic devices, PCs and wireless devices can be used for people to share, within the household or at a greater distance, photos, music, audio and video materials via networks. Ultra-Wide Band (UWB) system is regarded as excellent next generation of short-distance wireless indoor communication technique that is characterized by its low power consumption and high-speed data transport. As indicated by IEEE 802.15.3a standard, Ultra-Wide Band (UWB) system is permitted, in a definite way, to be operable in frequency ranges between 3.1 and 10.6 GHz. The system can also occupy a bandwidth greater than the center frequency 20% or at least a 500 MHz bandwidth. Since 1970s, wireless pulse techniques have been used in the development of the military communication system, and in recent years, these techniques have been allowed to be developed into high-performance wireless system and to be gradually commercialized. Furthermore, U.S. Federal Communication Committee (FCC) has mapped out the Ultra-Wide Band (UWB) system and thus is provided mature wireless pulse application.
Wireless carrier wave modulation is an appealing technology for wireless transport system because it does not need any complicated frequency mixer, intermediate frequency and filter circuits. Besides, expenses are lowered to a considerable extent. And fundamental frequency transport possesses better penetrability and thus is more suitable for indoor wireless communication system. In former times, some complicated electronic circuits and radio frequency components are adopted for wireless pulse communication to generate serial pulse signals. For example, FIGS. 1 and 2 show the traditional electric pulse generating devices.
In addition, in June 2002, on pages 206-208 of the twelfth volume of IEEE Microwave and Guided Wave Letters, Jeongwoo Han and Cam Nguyen put forward an electronic device that used a simple RC high-pass filter as a differentiator to generate Gaussian monocycle pulse.
In May 2004 issue of Circuits and Systems, 2004, ISCAS '04 and on pages 129-32 of the fourth volume of Proceedings of the 2004 International Symposium, Youngkyun Jeong, Sungyong Jung, Jin Liu came up with a Gaussian monocycle pulse generator by way of UMC 0.18 (μm) CMOS. The generator thus made is simpler and can generate pulses of wider bandwidth.